<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      let current = null;

      function App() {
        const ref = useRef();
      }

      function useRef() {
        if (!current) {
          console.log("重新创建ref");
          current = "ref";
          return "ref";
        } else {
          console.log("直接返回旧的current");
          return current;
        }
      }

      App();
    </script>
  </body>
</html>
